The following was initially posted on Pump.io, before I realised that this might benefit from a more preservable/visible format.
Frustrated with only interacting with my ownCloud calendar through the native web interface, I finally decided to look for a replacement application that I could run locally. Khal ended up being it, with vdirsyncer for two-way CalDAV sync with ownCloud.
Coupled with watdo, by the same author as vdirsyncer, for todo.txt-like management of CalDAV tasks (VTODO), I can now do all my schedule and tasks management from the comfort of my own terminal, even without any connectivity!